The instant invention relates to mailing machines, and more particularly to mailing machines which are automatically turned on and off depending upon whether or not an envelope is present on the feed deck thereof for processing to a postage meter situated downstream of the feed deck.
There are now being developed for mailing machines electronic systems which automatically turn on the mailing machine in response to an envelope entering the machine and which, after a set amount of time when no other envelope has been fed thereto, turn off the mailing machine, thereby reducing electrical power consumption and noise. Such an automatic on/off system will utilize in-line sensors to detect the presence or absence of envelopes. Many mailing machines being marketed today include the capability of printing indicia on envelopes fed seriatim manually thereto or automatically from a stack placed on a feed deck. In order to provide a mailing machine with an automatic on/off system which can accommodate both manual and automatic feeding, a sensor is required which can sense the presence of a single envelope at a given location, as well as a stack of envelopes at same given location without the stack height being limited by the physical limitations of the sensor.
Accordingly, the instant invention provides a sensor which can be utilized in an automatic on/off mailing machine capable of processing manually fed envelopes as well as envelopes fed automatically from a stack of envelopes stored in a supply hopper and which imposes no limitation on the height of the stack of envelopes stored in the supply hopper.